The EWRP Project, Eskene West Rail Project, consists of 15 buildings designed for the production and the storage of sulphur. The final product is finally loaded on freight trains, at a rate of roughly 4500 tons of sulphur per day.

The main bulding is the Sulphur Pastilliation Building, intended for hosting the process activities related with the transformation of the raw sulphur into pastilles, to be performed in an ATEX Zone 21. Around the main building, a number of industrial auxiliary buildings are located: an eletric sub-station, an administrative building, a fire station, a control station for the railway operations, and finally additional buildings where management and process functions are carried out. In case of an external emergency, two of the buildings can become temporary refuges. The HVAC installation and the control system are able to provide a three hours survival time to the people sheltered inside.

The external atmosphere is classified as dangerous, due to the presence of corrosive and harmful gases as strongS and SO2. This peculiarity requires that all buildings are equipped with chemical filters for the HVAC intake air, to ensure its breathability and the integrity of the electric and electronic machinery inside the buildings.

In emergency conditions, the external atmosphere can become a ATEX Zone 1. Therefore, the temporary refuges are equipped with a 15 meter chimney in order to guarantee to the HVAC system an explosive-gases-free air intake, to be used to pressurize the refuges. In order to guarantee an elevated safety standard, the whole mechanical system, the instrumentation chain, the access manoeuvres and the operating conditions of the refuges were designed to comply with a Safety Integrity Level (SIL) 2.

During the design process, the compliance of the safety level with the relative standards was verified by a third party (DNV).

The architecture of the system guarantees the functionality of the system even during emergencies. The building is pressurized in order to prevent the contaminated flow to penetrate, even during the access phase to the refuge when the opening of the external doors is required.

TRILLINI Engineering was responsible for the whole design of the HVAC system, from the preliminary study to the detailed design of the components, from the layout of the HVAC control board to the AHU, from the electro-instrumental system to the auxiliary equipment (compressed air production skid, chimneys, structures).

After the design phase, TRILLINI Engineering was in charge of controlling the technical uniformity of economical offers and of the suppliers follow-up, from the design phase to the conclusion of the work. Eventually, the company was responsible of verifying and running FAT on the main items, including control boards, AHU and chemical filters.

The complexity of the project was increased by the need of integrating the HVAC system with the main system, without compromising the safety levels. The challenge was won thanks to an efficient work organization, thanks to which TRILLINI Engineering was able to satisfy the client requirements and the problems which rose during the project engineering.

• External operating condition: -36 C to 45 C – RH 100%;
• Corrosive and explosive atmosphere (strongS-SO2);
• Internal pressurization;
• SIL Assesment (Temporary Refuge);
• ATEX.